Enhancement of oral bioavailability of vitamin E by spray-freeze drying of whey protein microcapsules

Vitamin E microcapsules were effectively prepared using three different techniques: spray drying, freeze-drying and spray freeze-drying with whey protein isolate as an encapsulating agent. The quality of microcapsules was evaluated by particle size distribution, surface morphology, encapsulation efficiency, moisture content, flow properties (Hausner ratio), dissolution properties and in vivo oral bioavailability. Vitamin E microcapsules prepared by spray drying, freeze-drying and spray freeze-drying techniques showed maximum encapsulation efficiencies of 89.6 ± 2.58, 86.1 ± 1.44, and 89.3 ± 2.56 respectively. Both freeze-dried and spray freeze-dried microcapsules showed excellent dissolution behavior with higher ODmax and dissolution rates (k0) than the spray-dried microcapsules due to the presence of numerous porous internal structures. Oral bioavailability study performed in male Wistar rats showed enhanced values of maximum plasma concentration (Cmax) and area under the curve (AUC) for spray freeze-dried microcapsules. The overall results demonstrate that the spray freeze-drying based microencapsulation technique could be a promising strategy to enhance the oral bioavailability of poorly water-soluble bioactive compounds like vitamin E.